Hi, I apologize if this is off topic. I'm not sure where to direct this question. I'm interested in when one can say that one theory is reducible to another. Reducibility is defined: a set A is T-reducible to a set B if there is a function f of type T such that x is a member of A if and only if f(x) is a member of B. Mathematical groups are defined in terms of a 0 element, other elements, and an operation with certain properties. Let A be the set of mathematical groups (set of models of groups?). Is there an interesting set B and function type T so that A is T-reducible to B? First of all, is that an interesting question to ask? If so, how would one go about thinking about it? Thanks for any help or pointers you can give me. -- Russ Abbott ______________________________________ Professor, Computer Science California State University, Los Angeles cell: 310-621-3805 Google voice: 424-2Blue4 blog: http://russabbott.blogspot.com/ vita: http://sites.google.com/site/russabbott/ ______________________________________ [For admin and other information see: http://www.mta.ca/~cat-dist/ ]